Recently there has been a trend to develop materials possessing an antimicrobial property generally utilizing a metal, e.g., silver, copper, zinc, etc. Metallic articles, especially stainless steel sheets, are known for their hygienic cleanliness. For example, with stainless steel, it is known to add antibacterial properties using metallic layers or alloy layers of chromium, titanium, nickel or iron containing silver, copper and/or zinc formed on their surface by sputtering or incorporating silver in the stainless steel and dispersing silver phases. In addition, it has been known for a long time that silver ions or copper ions or zinc ions have an antibacterial property. For example, a silver ion has widely been used as a disinfectant in the form of silver nitrate. However, the use of silver nitrate as a solution is inconvenient for handling and would have limited durability.
Generally, the incorporation of silver into a metal object or article itself has the disadvantage that the metal's characteristics are altered by the inclusion of the silver as well as the disadvantage of the high cost of the metals themselves. Such a metallic sheet or plate having the antibacterial ingredient deeply imbedded inside the sheet or plate does not exert any effective action upon bacteria attached to the surface making incorporation throughout the entire article uneconomical.
Known thermoset resin compositions have been broadly used as coating materials for various metals such as iron, aluminum, copper, and stainless steel since the compositions afford a coating which is superior in luster, transparency, hardness, weather resistance, chemical resistance and other properties. However, the coating, itself would have no antibacterial action in and of itself and such coatings often have insufficient adhesion to metals making it impossible to endure a forming process such as bending. As is apparent from the foregoing, an object of the present invention is to provide an antibacterial resin composition for coating of metals which withstands bending or forming processes and is usable for coated metal sheets.